Electronic metering apparatus for metering liquids

ABSTRACT

An electronic metering apparatus for metering liquids with a drive, at least one displacer device with a displacer chamber and a displacer element arranged therein, which is connected to the drive, at least one holding device for a pipette point, which has a passage channel which is connected with the displacer chamber, a data memory with memory locations for different calibration data concerning different pipette points and/or different liquids and/or different usage conditions, an electric selection device for selecting calibration data, an electric control unit, which is connected to the electric selection device, the data memory, and to the electric drive motor of the drive and/or an electric display device, and which controls the movement of the displacer element by means of the electric motor and/or the display of the metering volume through the display device with recourse to the calibration data from the data memory, selected with the aid of the selection device, and an electric power supply.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not applicable.

BACKGROUND OF THE INVENTION

The present invention is related to an electronic metering apparatus formetering liquids.

Known electronic metering apparatuses for metering liquids have a drivewith an electric motor and an electronic display device, respectively,and a displacer device driven by the motor, which comprises a cylinderwith a plunger arranged movable therein. The displacer device can becommunicatingly connected to a replaceable pipette point. By means ofthe displacer device, an air cushion is dislocated, which aspiratesliquid into the pipette point and ejects it from the same, respectively.Pipette points and syringes are preferably disposable objects for singleuse, made from a plastic material. The stroke volume of the plunger doesnot exactly correspond to the picked-up and delivered liquid volume.This is particularly due to the fact that the air column becomessomewhat longer through the weight of the liquid, so that the strokevolume exceeds the liquid volume.

From WO 2005/079988 A1, the entire contents of which is incorporatedherein by reference, a pipette with an electronic display and acalibration function is known. The calibration function includes theinput of an actually pipetted volume at a certain displayed volume intothe control system of the pipette via a user interface. The controlsystem calculates calibration data and memorizes them in a memory. Bymeans of the calibration data, the stroke length of the plunger or thevolume displayed by the display device is corrected, so that thedisplayed volume corresponds better to the actually metered volume. Itis possible to memorize different calibration data in the controlsystem, which are used for different pipetting functions (also called“modes of operation”), like direct pipetting or reverse pipetting.Direct pipetting includes the direct pick-up of the desired volume to bedelivered, whereas reverse pipetting includes the pick-up of a volumewhich is greater than the desired volume to be delivered, which isdelivered thereafter.

In the known pipette, a new calibration may become necessary, when oneof the provided modes of operation is not selected but other conditionsof operation are changed instead.

Departing from this, the present invention is based on the objective toprovide an electronic metering apparatus, the use of which underdifferent modes of operation is less impaired by calibrations.

BRIEF SUMMARY OF THE INVENTION

The electronic metering apparatus for metering liquids has a drive, atleast one displacer device with a displacer chamber and a displacerelement arranged therein, which is connected to the drive, at least oneholding device for a pipette point, which has a passage channel which isconnected with the displacer chamber, a data memory with memorylocations for different calibration data concerning different pipettepoints and/or different liquids and/or different usage conditions, anelectric selection device for selecting calibration data, an electriccontrol unit, which is connected to the electric selection device, thedata memory, and an electric drive motor of the drive and/or an electricdisplay device, and which controls the movement of the displacer elementby means of the electric motor and/or the display of the metering volumethrough the display device with recourse to the calibration data fromthe data memory, selected with the aid of the selection device, and anelectric power supply.

The metering apparatus according to the present invention permits asimple calibration, by selection of memorized calibration dataconcerning different pipette points and/or different liquids and/ordifferent conditions of application. Through this, it is possible tocontinue working under different conditions of operation, immediatelyafter selection of the calibration data corresponding to the newconditions of operation, which result from a replacement of the pipettepoint (for instance, with another geometry from another material or withanother surface, respectively), or from metering another liquid (forinstance with another density or viscosity, respectively) or from achange of the conditions of application (for instance, differentenvironmental conditions, like temperature, air pressure, air humidity,or different pipetting techniques like dipping in the pipette point intothe liquid to different depths or different alignment or movement of thepipette). It is not necessary to perform a calibration of the meteringapparatus under the new conditions of operation immediately before. Inthis, the selection can be restricted to one kind of the mentionedcalibration data or it may comprise several different kinds or all thekinds of the calibration data.

According to a first alternative, making recourse to the selectedcalibration data from the data memory, the control unit controls thedrive motor such that the displacer element aspirates exactly as muchliquid as is desired into the pipette point or ejects it from the same,respectively. According to a second alternative, at a given movement ofthe displacer element, making recourse to the calibration data, thecontrol unit controls the display such that the display exactlycorresponds to the liquid volume which was picked up or ejected,respectively. The second alternative may be either a metering apparatuswith a drive with an electric drive motor, or a metering apparatus witha manually driven drive. In a manually driven electronic meteringapparatus, the drive has an actuation element, which can be manuallydislocated between two stops and accordingly dislocates the displacerelement. In this, at least one stop for setting the metering volume orfor a manufacturer's calibration, respectively, may be dislocatable.

The present invention is related to stationary working meteringapparatuses as well as to manual metering apparatuses, also called“handheld metering apparatuses”.

According to one embodiment, the calibration data are calibration datafor pipette points of different geometry (e.g. conical, cylindrical orwith conical and cylindrical portions) and/or from different materials(e.g., PE, PP or PS) and/or with different surfaces (roughnesses, forinstances) and/or calibration data for different liquids (for instance,ethanol, propanol) and/or for different types of liquids (e.g.glycerol-, protein solutions) and/or calibration data for at least oneenvironmental condition (for instance, temperature, air pressure, airhumidity) and/or calibration data for at least one application (forinstance, not wetted pipette point or pipette point which is pre-wettedbefore metering) and/or calibration data for at least one user (forinstance depth of dipping into sample liquid, alignment of the pipettewith respect to the vertical, movement of the pipette point).

According to one embodiment, the data memory comprises a non-volatiledata memory (an EEPROM, for instance), so that calibration data are notlost when switching off the power supply. According to a furtherembodiment, the calibration data comprises permanently memorizedcalibration data. In this, it is dealt with calibration data which mustnot be erased or overwritten, respectively. The latter are calibrationdata, for instance, onto which must be recurred frequently or which donot change during the life span of the metering apparatus (for certainpipette points, certain liquids or frequent usage conditions like normaltemperature and normal pressure, for instance). Accordingly, the datamemory is for instance a permanent memory, (a ROM, for instance) or atleast partly write-protected.

The calibration data can be introduced into the data memory before usingthe metering apparatus, so that when using, only a selection of therelevant calibration data has to be performed, in principle. As the casemay be, the calibration data can be updated or supplemented later,respectively. The calibration data can be written into the data memoryin different ways. For instance, it is possible to acquire thecalibration data by suitable methods and to write them into the datamemory via an electric input device, which is connected to the electriccontrol unit. For instance, the calibration data can be acquired bygravimetric measurements and analysis of the measurements, which as thecase may be the user performs using an external data processingequipment with a suitable software, for instance. Also, it is possibleto calculate further calibration data departing from existingcalibration data, which apply for a changed geometry of the pipettepoints and/or liquids with another density and/or another temperatureand/or another air pressure and/or another dip-in depth of the pipettepoint and/or another alignment of the pipette with respect to thevertical. In particular, the calculation bases can be taken from themathematical model described in EP 0 562 358 B2 in paragraphs [0019] to[0034], the entire contents of which is incorporated herein byreference. The user can also perform these calculations, as the case maybe, using an external data processing equipment with a suitablesoftware. Further, it is possible to perform this calculation of thecalibration data by means of the control unit, wherein the dataconcerning different pipette points and/or different liquids and/ordifferent application conditions are input into the electronic meteringapparatus via an electric input device.

One embodiment has an electric input device for putting in at least onegravimetrically acquired volume and/or at least one density of a liquidand at least one gravimetrically acquired mass of the liquid, whereinthe control unit calculates calibration data from the gravimetricallyacquired volume and/or calculates a gravimetric volume and calibrationdata therefrom from the density and the gravimetrically determined mass,and writes the calibration data into the data memory. In thisembodiment, the results of the gravimetric measurement are input intothe metering apparatus in which the calibration data are calculated.There is no awesome calculation of the calibration data by the user. Theresults of the gravimetric measurement are transformed into calibrationdata by the metering apparatus and the same are stored in the datamemory. In the variant which permits the input of the mass and thedensity of the liquid, the step of the volume calculation by the user isalso avoided.

According to a further embodiment, plural gravimetric measurement valuescan be put in by means of the input device, from which the control unitdetermines the calibration data for a multipoint calibration, which itwrites into the data memory. A multipoint calibration permits aparticularly accurate measurement across a large range of settablemetering volumes.

The electric selection device for selecting calibration data isintegrated into a docking station for instance, which accommodates theelectronic metering apparatus in usage breaks. The docking station maycontain a charger for charging accumulators of the electric power supplyof the metering apparatus. It determines the environmental conditions(temperature, air pressure, air humidity) and forwards these data viacontacts or in a wireless manner to the electric control unit, whichmakes recourse to the corresponding calibration data in the operation ofthe metering apparatus, wherein the latter can be arranged in thedocking station or can be taken out of it. According to anotherembodiment, the selection device is integrated into the meteringapparatus such that upon use of the metering apparatus, it detectsautomatically the respective used pipette points and/or the applicationconditions at a time, and supplies corresponding data to the controlunit, which on its turn makes recourse to the corresponding calibrationdata. For instance, the pipette point used can be detected by a codeattached thereon which is read by a reading device of the meteringapparatus when the pipette point is put into the metering apparatus. Theliquid used can be acquired by a reading device of the meteringapparatus by reading a tag (like a barcode, for instance) of a storagebottle, for instance. Application conditions like temperature, airpressure, air humidity, dip-in depth of the pipette point and alignmentof the metering apparatus with respect to the vertical can be detectedby means of suitable sensors of the metering apparatus.

According to one embodiment, the electric metering apparatus comprisesan electric input device for putting in and/or selecting calibrationdata concerning different pipette points and/or different liquids and/ordifferent application conditions. On account of the input or selecteddata, respectively, the control unit makes recourse to the assignedcalibration data. According to one embodiment, the input device is anelectric keyboard.

According to a further embodiment, the electric input device has atleast two keys (called “mode key” and “parameter key”), the actuation ofwhich triggers that the control unit controls the display of differentmenus by the display device or the entry of displayed inputs.

According to a further embodiment, the input device has a pair ofelectric control keys arranged next to each other, and the electriccontrol unit controls the display of menu items by the display device,as well as the change of parameters and the display thereof by thedisplay device, corresponding to the actuation of the control keys.According to a further embodiment, the electric control unit controlsthe dislocation of the displacer element by the electric motor,corresponding to the actuation of the control keys.

The above embodiments of the input device facilitate the operation ofthe metering apparatus. In particular, they permit a simple selection ofcalibration data and a simple input of results of gravimetricmeasurements.

According to one embodiment, the input device permits the setting ofdifferent modes of operation (like pipetting, dispensing or titrating,for instance) and/or the setting of metering parameters (like meteringamount, dispensing steps, plunger speed when aspirating and ejectingliquid, for instance) and/or the control of the movement of thedisplacer element.

According to one embodiment, the input device has a turnable settingbutton for setting the mode of operation of the metering apparatus.

According to one embodiment, the electric control unit comprises amicroprocessor or a microcontroller.

The electric power supply supplies the electric components of themetering apparatus with electric current. According to a furtherembodiment, the electric power supply comprises a mains power packand/or at least one battery and/or at least one accumulator and/or anelectric charger for charging the accumulator.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the following, the present invention will be explained in more detailby means of the attached drawings of examples of its realization. In thedrawings show:

FIG. 1 an electronic metering apparatus in a perspective X-ray image,skew from the front and from the side;

FIG. 2 the same metering apparatus in a view from the side;

FIG. 3 the same metering apparatus in the same perspective view as inFIG. 1, but without representation of components situated in theinterior;

FIG. 4 the front side of the housing head of the metering apparatus indifferent operating situations in a schematic top view;

FIG. 5 the front side of the housing head of a metering apparatuswithout setting button in different operating situations in a schematictop view.

DETAILED DESCRIPTION OF THE INVENTION

While this invention may be embodied in many different forms, there aredescribed in detail herein a specific preferred embodiment of theinvention. This description is an exemplification of the principles ofthe invention and is not intended to limit the invention to theparticular embodiment illustrated

According to FIG. 1 to 3, a metering apparatus 1 has a housing 2realized as a handle, with a longitudinal housing shaft 3 and a housinghead 4 angled at about 45° on the upper end. The housing 2 has a cone 5at the lower end for putting up a pipette point 6.

In the housing shaft 3, a drive 7 with an electric motor 8 is arranged.Further, there is a cylinder 9 with a longitudinally movable plunger 10arranged therein, which is mechanically connected with the drive 7. Viaa connecting channel 11, the cylinder 9 is connected to an opening atthe end of the cone 5.

On its lower side, the housing head 4 has a downward bent hook 12, whichfacilitates securely holding the metering apparatus 1 on the housingshaft 3. At the upper end of the housing shaft 3, a discarder key 13 isarranged, which is mechanically connected with a discarder sleeve 14, sothat by actuation of the discarder key 13, a pipette point 6 can bepushed off from the cone 5.

On the topside or front side, respectively, of the housing head 4 thereis a display device 16 or a display, respectively, which is realized asa LCD display. Above the display device 16, there is a turnable settingbutton 17 for rapidly setting the modes of operation.

Below the display device 16, a mode key 18 and a parameter key arearranged laterally off-set to each other. Between them, there are twocontrol keys 20, 21 on top of each other, wherein the upper control key20 controls an upward movement and the lower control key 21 controls adownward movement and an overblow stroke.

The control key 20 has only one single switching point. The control key21 has two switching points, wherein reaching the first switching pointtriggers the downward movement and reaching the second switching pointtriggers an overblow stroke of the plunger 10.

In the housing head 4, an electric control unit 22 is arranged on acircuit board, which is connected with the electric motor 8, the displaydevice 16, the setting button 17 and the keys 18 to 21. Preferably, theelectric control unit 22 comprises an electronic data processing unit, amicrocomputer or a microcontroller for instance.

Further, there is a data memory 23, which is at least one separatecomponent part or is integrated into the microcontroller.

Further, an electric power supply 24 is present in the housing head 4,which is formed by several accumulators for instance, which can becharged by means of an external charger. The electric power supply 24supplies the electric component parts of the metering apparatus 1 withelectric current.

From a standby mode, into which it falls after a certain idle period,the electronic metering apparatus 1 can be brought into the normaloperating condition by actuating an arbitrary key 18 to 21. In additionor instead of this, a not shown on/off-switch can be present forswitching on the normal operating condition or switching it off,respectively.

After switching on, the display device shows a submenu with the lastlyset mode of operation and the lastly set metering parameters of thismode of operation.

In FIG. 4.1, this is shown for the case that the mode of operationpipetting (“pip”) is set by means of the setting button 17.

After actuation of the mode key 18, it is possible to change meteringparameters of this mode of operation. In FIG. 4.2, the display device 16after actuation of the mode key 18 is shown. The changeable meteringparameter (the metering volume 100 μl here) is graphically accentuated(by color, for instance), through a lighter grey tone here.

Thereafter, through actuation of the control keys 20, 21, the value ofthe metering parameter can be increased or decreased, respectively. InFIG. 4.3 this is shown for a reduction of the metering volume (to 80μl).

Through actuation of the parameter key 19, the set metering parameter istransferred and is switched over to another changeable meteringparameter, which the display device 16 indicates by graphic accentuation(FIG. 4.4). Here, this is the plunger speed when ejecting liquid (5mm/s). This metering parameter can then be changed with the aid of thecontrol keys 20, 21, to 8 mm/s in the example (FIG. 4.5). Thereafter,the change can be transferred by newly actuating the parameter key 19and can be switched over to the plunger speed when aspirating, which isindicated by graphical accentuation (FIG. 4.6). This metering parametercan be changed by means of the control keys 20, 21, here to 10 mm/s(FIG. 4.7).

Through actuation of the mode key 18, it is possible to transfer thelast change and to switch back from the editing mode to the pipettingmode. Thereafter, by actuation of the control key 20, a volume of 80 μlof liquid can be picked up into the pipette point (FIG. 4.8) and bedelivered by actuation of the control key 21 (FIG. 4.9).

By turning the setting button 17, other modes of operation are reached,for instance manual pipetting (“man”), pipetting and mixing (“pip undmix”) dispensing (“dis”), automatic dispensing (“auto dis”), titrating(“ttr”), gel loading (“gel”) and reverse pipetting (“rev”).

By setting the setting button 17 to the position options (“opt”), asubmenu is invoked on the display device 16 (FIG. 4.10), from which byactuation of the control keys 20, 21 different menu items can be steeredfor, to which a pointer 25 points (FIG. 4.11). Through actuation of theparameter key 19, one single menu item can be selected.

When the menu item “Justage” (adjustment) is selected, a submenu appearswhich is concerned with the selection or the input, respectively, ofdifferent calibration parameters (FIG. 4.12). Through actuation of thecontrol keys 20, 21 certain menu items can be steered for and can beselected by actuation of the parameter key 19 (FIG. 4.13). Thus, forinstance the calibration parameters of the manufacturer's setup, forethanol or glycerol or for a particularly long pipette point (“SpecialTip long”) can be selected (FIG. 4.12). It is also possible to selectthe calibration parameters for certain geographical altitudes at whichthe pipette is used (FIG. 4.13).

Furthermore, after selecting the corresponding menu items, thegravimetric values for endpoint, two-point or three-point adjustment canbe put in (FIG. 4.13).

By turning the setting button 17, the user reaches the menu in which theselected mode of operation with the actual parameters is indicated (forinstance, FIG. 4.9).

Thereafter, he/she can meter in the selected mode of operation, whereinthe control unit makes recourse to the selected calibration data, whichare memorized in the data memory 23. As the case may be, the meteringparameters effective in the mode of operation can be changed in themanner described above.

FIG. 5 shows the top side 15 of the housing head 4 of a further meteringapparatus, which has no setting wheel 17. The modes of operation of thismetering apparatus are selected via the menu indicated by the displaydevice 16 and the keys 18 to 21.

For this purpose, the mode key 18 is pushed, departing from theautomatically appearing display for the lastly selected mode ofoperation with the lastly set metering parameters (5.1), after which amenu with the selectable modes of operation is displayed (FIG. 5.2). Bymeans of the control keys 20, 21, the pointer 25 is set to a desiredmode of operation (FIG. 5.3). In order to confirm the mode of operation,the parameter key 19 is pushed, after which the selected mode ofoperation with the lastly set metering parameters is displayed (FIG.5.4).

For the rest, the operation takes place as with the above-describedembodiment of FIG. 1 to 4, with a setting wheel for setting the mode ofoperation. In particular, the metering parameters, the execution ofmetering processes in selected modes of operation, the selection ofcalibration data as well as the input of the results of gravimetricmeasurements takes place as in the example of realization describedabove.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. All these alternatives and variations areintended to be included within the scope of the claims where the term“comprising” means “including, but not limited to”. Those familiar withthe art may recognize other equivalents to the specific embodimentsdescribed herein which equivalents are also intended to be encompassedby the claims.

Further, the particular features presented in the dependent claims canbe combined with each other in other manners within the scope of theinvention such that the invention should be recognized as alsospecifically directed to other embodiments having any other possiblecombination of the features of the dependent claims. For instance, forpurposes of claim publication, any dependent claim which follows shouldbe taken as alternatively written in a multiple dependent form from allprior claims which possess all antecedents referenced in such dependentclaim if such multiple dependent format is an accepted format within thejurisdiction (e.g. each claim depending directly from claim 1 should bealternatively taken as depending from all previous claims). Injurisdictions where multiple dependent claim formats are restricted, thefollowing dependent claims should each be also taken as alternativelywritten in each singly dependent claim format which creates a dependencyfrom a prior antecedent-possessing claim other than the specific claimlisted in such dependent claim below.

This completes the description of the preferred and alternateembodiments of the invention. Those skilled in the art may recognizeother equivalents to the specific embodiment described herein whichequivalents are intended to be encompassed by the claims attachedhereto.

1. An electronic metering apparatus for metering liquids with a drive(7, 8), at least one displacer device (9, 10) with a displacer chamber(9) and a displacer element (10) arranged therein, which is connected tothe drive (7,8), at least one holding device (5) for a pipette point(6), which has a passage channel (11) which is connected with thedisplacer chamber (9), a data memory (23) with memory locations fordifferent calibration data concerning different types of calibrationparameters which are selected from the group comprising differentpipette points, different liquids and different usage conditions, anelectric selection device (18, 19, 20, 21) for selecting the calibrationparameter, an electric control unit (22), which is connected to theelectric selection device (18, 19, 20, 21), the data memory (23), and tothe electric drive motor (8) of the drive (7, 8) and to an electricdisplay device (16), and which controls the movement of the displacerelement (10) by means of the electric motor (8) and the display of themetering volume through the display device (16) making recourse to thecalibration data from the data memory (23), selected with the aid of theselection device (18, 19, 20, 21), and an electric power supply (24),characterized in that the memorized calibration data concerningdifferent types of calibration parameters are displayable on the displaydevice (16) by means of the selection device (18, 19, 20, 21) andwherein at least one calibration parameter may be selected forperforming at least one metering with the selected calibrationparameter.
 2. A metering apparatus according to claim 1, which is ahandheld metering apparatus.
 3. A metering apparatus according to claim1, wherein the calibration data comprise calibration parameters whichare selected from the group comprising pipette points (6) of differentgeometry and from different materials and with different surfaces anddifferent liquids and different types of liquids and at least oneenvironmental condition and at least one application and at least oneuser.
 4. A metering apparatus according to claim 1, wherein the datamemory (23) comprises a non-volatile data memory.
 5. A meteringapparatus according to claim 1, wherein the data memory (23) comprisespermanently memorized calibration data.
 6. A metering apparatusaccording to claim 1, which has an electric input device (18, 19, 20,21) for putting in at least one gravimetrically determined volume or atleast one density of a liquid and at least one gravimetricallydetermined mass of the liquid, wherein the control unit (22) calculatescalibration data from the gravimetrically determined volume orcalculates a gravimetric volume and calibration data therefrom from thedensity and the gravimetrically determined mass, and writes thecalibration data into the data memory (23).
 7. A metering apparatusaccording to claim 6, wherein plural gravimetric measurement values canbe input by means of the input device (18, 19, 20, 21), from which thecontrol unit (22) determines the calibration data for a multipointcalibration, which it writes into the data memory (23).
 8. A meteringapparatus according to claim 1, wherein the electric selection device(18, 19, 20, 21) comprises an electric input device for putting in andselecting calibration data concerning different pipette points (6) anddifferent liquids and different application conditions.
 9. A meteringapparatus according to claim 6, wherein the electric input device (18,19, 20, 21) comprises at least one mode key (18) and a parameter key(19), the actuation of which triggers that the control unit (22)controls the display of different menus by the display device (16) orthe entry of displayed inputs.
 10. A metering apparatus according toclaim 6, wherein the input device (18, 19, 20, 21) has a pair ofelectric control keys (20, 21) disposed next to each other, and theelectric control unit (22) controls the display of menu items by thedisplay device (16) as well as the change of parameters and the displaythereof by the display device (16), corresponding to the actuation ofthe control keys (20, 21).
 11. A metering apparatus according to claim10, wherein the electric control unit (22) controls the dislocation ofthe displacer element (10) by the electric motor (8), corresponding tothe actuation of the control keys (20, 21).
 12. A metering apparatusaccording to claim 6, wherein the input device (18, 19, 20, 21) permitsthe setting of different modes of operation or the setting of meteringparameters or the control of the movement of the displacer element (10).13. A metering apparatus according to claim 6, wherein the input devicecomprises a turnable setting button (17) for setting the mode ofoperation of the metering apparatus.
 14. A metering apparatus accordingto claim 1, wherein the electric control unit (22) comprises amicroprocessor or a microcontroller.
 15. The electronic meteringapparatus of claim 1 wherein the calibration parameter is differentpipette points.
 16. The electronic metering apparatus of claim 15wherein an additional calibration parameter is different liquids. 17.The electronic metering apparatus of claim 16 wherein an additionalcalibration parameter is different usage conditions.